Method and device for controlling a magnetic resonance imaging system as part of functional magnetic resonance imaging

Abstract

In a method for controlling a magnetic resonance imaging system as part of functional magnetic resonance imaging, a main magnetic field B0 is provided having a field strength of at most 1.4 tesla at a main field magnet system ( 4 ) of the magnetic resonance imaging system ( 1 ); and a measurement is performed as part of functional magnetic resonance imaging, wherein a measurement sequence (MS) is applied that has a longer echo time TE (e.g. longer than 100 ms).

The invention claimed is: 
     
       1. A method for controlling a magnetic resonance imaging (MRI) system for functional magnetic resonance imaging, comprising:
 providing, by a magnet generator, a main magnetic field having a field strength of at most 1.4 T at a main field magnet system of the MRI system; and 
 providing, by a measurement controller, an echo-planar imaging (EPI) measurement sequence to the MRI system to perform a measurement as part of functional magnetic resonance imaging, wherein the EPI measurement sequence is a single-shot gradient echo EPI measurement sequence having an echo time longer than 100 ms and shorter than 500 ms, the echo time being set based on the field strength of the main magnetic field according to TE=A/B0, where the echo time is TE, the main magnetic field is B0, and A has a minimum value of 70 ms·T. 
 
     
     
       2. The method as claimed in  claim 1 , wherein the generated main magnetic field has a field strength of at most 1 T and greater than 0.3 T. 
     
     
       3. The method as claimed in  claim 1 , wherein the measurement sequence applied has an echo time longer than 150 ms and shorter than 500 ms. 
     
     
       4. The method as claimed in  claim 1 , wherein A has a maximum value of 90 ms·T. 
     
     
       5. The method as claimed in  claim 1 , wherein A has a maximum value of 100 ms·T. 
     
     
       6. The method as claimed in  claim 1 , wherein the measurement is configured to measure a T2 contrast or a T2* contrast. 
     
     
       7. The method as claimed in  claim 1 , wherein the measurement is performed by a balanced steady-state free precession sequence using a flip angle that is greater than 55°, wherein a Blood oxygenation level dependent (BOLD) effect is measured dynamically by the balanced steady-state free precession sequence in combination with T2 preparatory pulses. 
     
     
       8. The method as claimed in  claim 1 , wherein:
 readout gradients, phase-encoding gradients, and/or slice-selection gradients are applied at a reduced strength of 8 mT/m or less, and/or 
 a ramp time of the number of readout gradients, phase-encoding gradients, and/or slice-selection gradients is 150 μs. 
 
     
     
       9. The method as claimed in  claim 1 , wherein an active or passive implant is introduced into a head of the patient before the measurement. 
     
     
       10. The method as claimed in  claim 9 , wherein the active or passive implant is a deep brain stimulator. 
     
     
       11. The method as claimed in  claim 1 , wherein a Fast low angle shot magnetic resonance imaging (FLASH)/spoiled gradient echo readout is used to obtain the measurement. 
     
     
       12. The method as claimed in  claim 11 , wherein the FLASH/spoiled gradient echo readout is combined analogously with a T2 Prep pulse. 
     
     
       13. The method as claimed in  claim 1 , wherein the echo time is inversely proportional to the field strength of the main magnetic field. 
     
     
       14. The method as claimed in  claim 1 , wherein the generated main magnetic field has a field strength greater than 0.2 T and at most 1 T. 
     
     
       15. A computer program product having a computer program which is directly loadable into a memory of a controller of the MRI system, when executed by the controller, causes the MRI system to perform the method as claimed in  claim 1 . 
     
     
       16. A non-transitory computer-readable storage medium with an executable program stored thereon, that when executed, instructs a processor to perform a method for controlling a magnetic resonance imaging (MRI) system for functional magnetic resonance imaging, wherein the method comprises:
 controlling MRI system to provide a main magnetic field having a field strength of at most 1.4 T at a main field magnet system of the MRI system; and 
 providing, to the MRI system, a balanced steady-state free precession sequence using a flip angle that is greater than 55° to perform a measurement as part of functional magnetic resonance imaging, wherein:
 the balanced steady-state free precession sequence has an echo time longer than 100 ms and shorter than 500 ms, the echo time being set based on the field strength of the main magnetic field according to TE=A/B0, where the echo time is TE, the main magnetic field is B0, and A has a minimum value of 70 ms·T, and 
 a Blood oxygenation level dependent (BOLD) effect is measured dynamically by the balanced steady-state free precession sequence in combination with T2 preparatory pulses. 
 
 
     
     
       17. A device for controlling a magnetic resonance imaging system as part of functional magnetic resonance imaging, comprising:
 a magnetic-field generator configured to provide a main magnetic field having a field strength of at most 1.4 T at a main field magnet system of the magnetic resonance imaging system; and 
 a measurement controller configured to provide a measurement sequence having an echo time that is longer than 100 ms and shorter than 500 ms, and perform a Fast low angle shot magnetic resonance imaging (FLASH)/spoiled gradient echo readout, to perform a measurement as part of the functional magnetic resonance imaging, the FLASH/spoiled gradient echo readout being combined analogously with a T2 preparatory pulse, wherein the echo time is set based on the field strength of the main magnetic field according to TE=A/B0, where the echo time is TE, the main magnetic field is B0, and A has a minimum value of 70 ms·T. 
 
     
     
       18. The device as claimed in  claim 17 , wherein the echo time is longer than 150 ms and shorter than 500 ms. 
     
     
       19. A controller for controlling the magnetic resonance imaging system, comprising the device as claimed in  claim 17 . 
     
     
       20. A magnetic resonance imaging (MRI) system comprising:
 a MRI scanner, and 
 a controller including the device of  claim 17  that is configured to control the MRI scanner.